Recent research suggests that sleepiness and mind-wandering—the experience of thoughts that are both stimulus-independent and task-unrelated—frequently co-occur and are both associated with poorer ... [more ▼]

Recent research suggests that sleepiness and mind-wandering—the experience of thoughts that are both stimulus-independent and task-unrelated—frequently co-occur and are both associated with poorer cognitive functioning. Whether these two phenomena have distinguishable effects on task performance remains unknown, however. To investigate this question, we employed the online experience sampling of mind-wandering episodes and subjective sleepiness during a laboratory task (the Sustained Attention to Response Task; SART), and also assessed mind-wandering frequency and sleep-related disturbances in daily life using self-report questionnaires. The results revealed that the tendency to experience mind-wandering episodes during the SART and daily life was associated with higher levels of daytime sleepiness and sleep-related disturbances. Importantly, however, mind-wandering and sleepiness were independent predictors of SART performance at both the within- and between-individuals levels. These findings demonstrate that, although mind-wandering and sleepiness frequently co-occur, these two phenomena have distinguishable and additive effects on task performance. [less ▲]

Linear and Quadratic Discriminant Analysis (LDA/QDA) are the most often applied classification rules under the normality assumption. When there is not enough data, the quadratic rule, which requires the ... [more ▼]

Linear and Quadratic Discriminant Analysis (LDA/QDA) are the most often applied classification rules under the normality assumption. When there is not enough data, the quadratic rule, which requires the estimation of one precision matrix in each class, is often replaced by the linear one, based on the homoscedasticity assumption. This strong assumption is however rarely verified in practice and ignores the intrinsic différences between groups that may be of particular interest in the classification context. In this aper, alternatives to the usual maximum likelihood estimates for the precision matrices are proposed that borrow strength across classes while allowing for heterogeneity at the same time. This results in a classifier that is intermediate between QDA and LDA. Moreover, our estimator is sparse: the undesirable effect of uninformative variables is reduced. The performance of the method is illustrated through simulated and real dataset examples. [less ▲]

This article is about visual devices that in history of art and in semiotics are generally called "metavisual" and that are used to study some phenomena of framing in artistic images (see the works of ... [more ▼]

This article is about visual devices that in history of art and in semiotics are generally called "metavisual" and that are used to study some phenomena of framing in artistic images (see the works of Victor Stoichita and of Jean-François Bordron). We are going to explore the possibility to use these devices to analyse contemporary scientific images, trying to identify some common actions that go beyond the differences in terms of objects and economy of values between arts and sciences. [less ▲]

epiphytic filamentous algae (EFA) disease has appeared in many regions of Madagascar. This infestation has dramatic consequences for local farmers as it alters drastically farmed algal growth and has ... [more ▼]

epiphytic filamentous algae (EFA) disease has appeared in many regions of Madagascar. This infestation has dramatic consequences for local farmers as it alters drastically farmed algal growth and has caused farming activity to collapse in many places. The present study characterizes the structure and ultrastructure of the stages observed in the life cycle of Polysiphonia sp. and gives the results of a monitoring of 18 months made in three Kappaphycus alvarezii farming sites in the southwest of Madagascar. Transmission electron microscopy (TEM) was used to analyze the ultrastructure of the cortex in infested K. alvarezii. Five stages have been observed in the life cycle of Polysiphonia sp.: the infesting stage that is a small dark spot observed at the surface of K. alvarezii, the male gametophyte, the female gametophyte, the tetrasporocysts, and the undifferentiated stage where individuals show normal thalli without sexual differentiation. EFA infestation was never recorded in Sarodrano, but often in the two other monitored villages (Lambohara, Tampolove). Prevalence of infestation varied from 40 to 100 % and the rates of infestation from 42 to 78 epiphytes cm−2. Prevalence of infestation showed significant seasonal variation and a between-sites variation; the rates of infestation were not significantly different between sites and did not vary with the period. The ways of infestation between K. alvarezii individuals in an infested field and from infested to healthy fields are discussed at the light of the present results. [less ▲]

in Proceedings of the 6th European Innovative Smart Grid Technologies (ISGT) (2016, October)

There is a need to clearly state an interaction model that formalizes interactions between actors of the distribution system exchanging flexibility. In previous works we quantitatively evaluated the ... [more ▼]

There is a need to clearly state an interaction model that formalizes interactions between actors of the distribution system exchanging flexibility. In previous works we quantitatively evaluated the performance of five interaction models devised with industrial partners using the agent-based testbed DSIMA. Simulation results showed that these interaction models relying on active network management suffer from a lack of coordination between the distribution and the transmission system operator, activating flexibility simultaneously in opposite directions. This paper introduces a new interaction model fixing this issue based on dynamic access bounds to the network changing throughout the day and preventing the activation of flexibility leading to congestions. This new interaction model is implemented in DSIMA and compared to a model restricting the grid users to a very restrictive but safe access range. Results show that this new model allows to safely increase by 55% the amount of distributed generation in the network. [less ▲]

During tumour dissemination, invading breast carcinoma cells become confronted with a reactive stroma, a type I collagen-rich environment endowed with anti-proliferative and proapoptotic properties. To ... [more ▼]

During tumour dissemination, invading breast carcinoma cells become confronted with a reactive stroma, a type I collagen-rich environment endowed with anti-proliferative and proapoptotic properties. To develop metastatic capabilities, tumour cells must acquire the capacity to cope with this novel microenvironment. How cells interact with and respond to their microenvironment during cancer dissemination remains poorly understood. To address the impact of type I collagen on the fate of tumour cells, human breast carcinoma MCF-7 cells were cultured within three-dimensional type I collagen gels (3D COL1). Using this experimental model, we demonstrate that membrane type-1 matrix metalloproteinase (MT1-MMP), a proteinase overexpressed in many aggressive tumours, promotes tumour progression by circumventing the collagen-induced up-regulation of BIK, a pro-apoptotic tumour suppressor, and hence apoptosis. A transcriptomic analysis was performed to decipher the molecular mechanisms regulating 3D COL1-induced apoptosis in human breast cancer cells. Control and MT1-MMP expressing MCF-7 cells were cultured on two-dimensional plastic plates or within 3D COL1 and a global transcriptional time-course analysis was performed. Shifting the cells from plastic plates to 3D COL1 activated a complex reprogramming of genes implicated in various biological processes. Bioinformatic analysis revealed a 3D COL1-mediated alteration of key cellular functions including apoptosis, cell proliferation, RNA processing and cytoskeleton remodelling. By using a panel of pharmacological inhibitors, we identified discoidin domain receptor 1 (DDR1), a receptor tyrosine kinase specifically activated by collagen, as the initiator of 3D COL1-induced apoptosis. Our data support the concept that MT1-MMP contributes to the inactivation of the DDR1-BIK signalling axis through the cleavage of collagen fibres and/or the alteration of DDR1 receptor signalling unit, without triggering drastic alterations of the transcriptome of MCF-7 cells. [less ▲]

During breast carcinoma development, cells are confronted to a type I collagen-rich environment which induces anti-proliferative and pro-apoptotic effects (Maquoi et al., Oncogene, 2012). These effects occurred only in 3D cell matrix and involved Discoidin Domain Receptor 1 (DDR1) but not β1 integrin (Assent et al., PlosOne, 2015). During aging, type I collagen undergoes post-translational modifications which have a detrimental effect on type I collagen fibrillar organization (Aït-Belkacem, J Biomed Optics, 2012 ; Guilbert et al., Oncotarget, 2016). This property is well known to be requested to activate DDR1. Here, we address the effect of type I collagen aging on cell proliferation inhibition and apoptosis induction in breast carcinoma cells in 3D cell confinement system. Type I collagen was extracted from tail tendons of 2 months (adult) and 2 years (old) rats, and MCF-7 and ZR-75-1 cells were used as an experimental model. We provide evidence for a decrease in cell proliferation by adult collagen but not by old one. This effect involves a higher phosphorylation of DDR1 by adult collagen when compared to the old one. Inhibition of DDR1 kinase activity by the specific inhibitor DDR1-IN-1 induced an increase in cell proliferation to a level similar to that observed in old collagen. An increase in cell proliferation was also observed using siRNA targeting DDR1 mRNA. At the opposite of old collagen, adult collagen was also able to trigger apoptosis by inducing an increase in expression of the pro-apoptotic protein (BIK). Inhibition of DDR1 kinase activity induced a decrease in BIK expression and apoptosis. Our data support the concept that aging contributes to the loss of the growth suppression and apoptotic effect of collagen on breast carcinoma, but only in 3D cell confinement model, by inactivating the DDR1-BIK signaling axis via a downregulation of DDR1 activation. [less ▲]

With the increasing share of renewable and distributed generation in electrical distribution systems, active network management (ANM) becomes a valuable option for a distribution system operator to ... [more ▼]

With the increasing share of renewable and distributed generation in electrical distribution systems, active network management (ANM) becomes a valuable option for a distribution system operator to operate his system in a secure and cost-effective way without relying solely on network reinforcement. ANM strategies are short-term policies that control the power injected by generators and/or taken off by loads in order to avoid congestion or voltage issues. While simple ANM strategies consist in curtailing temporary excess generation, more advanced strategies rather attempt to move the consumption of loads to anticipated periods of high renewable generation. However, such advanced strategies imply that the system operator has to solve large-scale optimal sequential decision-making problems under uncertainty. The problems are sequential for several reasons. For example, decisions taken at a given moment constrain the future decisions that can be taken, and decisions should be communicated to the actors of the system sufficiently in advance to grant them enough time for implementation. Uncertainty must be explicitly accounted for because neither demand nor generation can be accurately forecasted. We first formulate the ANM problem, which in addition to be sequential and uncertain, has a nonlinear nature stemming from the power flow equations and a discrete nature arising from the activation of power modulation signals. This ANM problem is then cast as a stochastic mixed-integer nonlinear program, as well as second-order cone and linear counterparts, for which we provide quantitative results using state of the art solvers and perform a sensitivity analysis over the size of the system, the amount of available flexibility, and the number of scenarios considered in the deterministic equivalent of the stochastic program. To foster further research on this problem, we make available at http://www.montefiore.ulg.ac.be/~anm/ three test beds based on distribution networks of 5, 33, and 77 buses. These test beds contain a simulator of the distribution system, with stochastic models for the generation and consumption devices, and callbacks to implement and test various ANM strategies. [less ▲]

Co-simulation opens new opportunities to combine mature ElectroMagnetic Transients (EMT) and Phasor-Mode (PM) solvers, and take advantage of their respective high accuracy and execution speed. In this ... [more ▼]

Co-simulation opens new opportunities to combine mature ElectroMagnetic Transients (EMT) and Phasor-Mode (PM) solvers, and take advantage of their respective high accuracy and execution speed. In this paper, a relaxation approach is presented, iterating between an EMT and a PM solver. This entails interpolating over time the phasors of the PM simulation, extracting phasors from the time evolutions of the EMT simulation, and representing each sub-system by a proper multiport equivalent when simulating the other sub-system. Various equivalents are reviewed and compared in terms of convergence of the PM-EMT iterations. The paper also considers the update with frequency of the Thévenin impedances involved in the EMT simulation, the possibility to compute the EMT solution only once per time step, and the acceleration of convergence through a prediction over time of the boundary variables. Results are presented on a 74-bus, 23-machine test system, split into one EMT and one PM sub-system with several interface buses. [less ▲]